A kinematic limit analysis approach for masonry buildings: in- and out-of-plane failure mechanisms

摘要

Historical and existing masonry structures have usually an inadequate resistance tohorizontal actions. Furthermore, historical city centres present high vulnerability under horizontalloads and this is mostly due to the absence of adequate connections between the various parts [1][2]. This characteristic leads to overturning collapses of the perimeter walls under seismic loadsand combined in- and out-of-plane failures. Even if limit analysis is not sufficient for a fullstructural analysis under seismic actions, since it does not provide displacements at failure, it canbe used in order to have a quick estimation of both collapse loads and failure mechanisms [3].In this paper, the micro-mechanical model presented by the authors in [4] and [5] for the limitanalysis of respectively in- and out-of-plane loaded masonry walls [6] is utilized for the 3Danalysis of entire buildings. In the model, admissible and equilibrated polynomial stress fields areimposed in order to estimate the macroscopic masonry failure surface. Finally, such surface isimplemented in a FE kinematic limit analysis code and an example of technical relevance isdiscussed in detail.